body{
    display: flex;
    flex-direction: column;
    
    main{
        height: 1px;
        flex-grow: 1;
        overflow-y: auto;
    }

    // 底部导航
    nav{
        height: 77px;
        display: flex;
        justify-content: space-around;
        box-shadow: 0 -3px 5px #ccc;

        a{
            color: #777;
            text-align: center;
            font-size: 20px;

            &.on{
                color: #72a2ff;
            }

            .iconfont{
                display: block;
                font-size: 40px;
            }
        }
    }
}